Add readme for DBs and risc0 adapter (Sovereign-Labs#333)

* Add readme for schemadb and risc0 adapter

* Add README for Sovereign DB

* Update full-node/db/sovereign-db/README.md

Co-authored-by: Nikolai Golub <[email protected]>

* Update full-node/db/schemadb/README.md

Co-authored-by: Nikolai Golub <[email protected]>

---------

Co-authored-by: Nikolai Golub <[email protected]>

adapters/risc0/README.md

@@ -0,0 +1,13 @@
+# Risc0 Adapter
+
+This package adapts Risc0 version 0.14 to work as a ZKVM for the Sovereign SDK.
+
+## Limitations
+
+Since recursion is not included in the 0.14 release, this adapter is currently limited - individual "slots" may
+be proven, but those proofs cannot be recursively combined to facilitate bridging or ultra-fast sync.
+
+## Warning
+
+Risc0 is currently under active development and has not been audited. This adapter has also not been audited. Do not
+deploy in production

examples/demo-rollup/README.md

@@ -11,6 +11,8 @@ package instead.
 
 By swapping out or modifying the imported state transition function, you can customize
 this example full-node to run arbitrary logic.
+This particular example relies on the state transition exported by [`demo-stf`](../demo-stf/). If you want to
+understand how to build your own state transition function, check out at the docs in that package.
 
 ## How to Customize This Example
 

full-node/db/schemadb/README.md

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+# Schema DB
+
+This package is a low-level wrapper transforming [RocksDB](https://rocksdb.org/) from a byte-oriented key value store into a
+type-oriented store. It's adapted from a simliar package in Aptos-Core.
+
+The most important concept exposed by Schema DB is a `Schema`, which maps a column-family name
+codec's for the key and value.
+
+```rust
+pub trait Schema  {
+    /// The column family name associated with this struct.
+    /// Note: all schemas within the same SchemaDB must have distinct column family names.
+    const COLUMN_FAMILY_NAME: &'static str;
+
+    /// Type of the key.
+    type Key: KeyCodec<Self>;
+
+    /// Type of the value.
+    type Value: ValueCodec<Self>;
+}
+```
+
+Using this schema, we can write a generic functions for storing and fetching typed data and ensure that
+it's always encoded/decoded in the way we expect.
+
+```rust
+impl SchemaDB {
+	pub fn put<S: Schema>(&self, key: &impl KeyCodec<S>, value: &impl ValueCodec<S>) -> Result<()> {
+		let key_bytes = key.encode_key()?;
+        let value_bytes = value.encode_value()?;
+		self.rocks_db_handle.put(S::COLUMN_FAMILY_NAME, key_bytes, value_bytes)
+	}
+}
+```
+
+To actually store and retrieve data, all we need to do is to implement a Schema
+
+```rust
+pub struct AccountBalanceSchema;
+
+impl Schema for AccountBalanceSchema {
+	const COLUMN_FAMILY_NAME = "account_balances"
+	type Key = Account;
+	type Value = u64;
+}
+
+impl KeyCodec<AccountBalanceSchema> for Account {
+	fn encode_key(&self) -> Vec<u8> {
+		bincode::to_vec(self)
+	}
+
+	fn decode_key(key: Vec<u8>) -> {
+		// elided
+	}
+}
+
+impl ValueCode<AccountBlanceSchema> for u64 {
+	// elided
+}
+```

full-node/db/sovereign-db/README.md

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+# Sovereign DB
+
+This package provides a high-level interface to a [Schema DB](../schemadb/README.md) designed specifically for use with the Sovereign SDK.
+It exposes two db types: `LedgerDB`, and `StateDB`.
+
+## LedgerDB
+
+As the name implies, the `LedgerDB` is designed to store ledger history. It has tables for slots, batches, transactions, and events.
+The `LedgerDB` also implements the `LedgerRpcProvider` trait, allowing it to easily serve chain history over RPC
+
+## StateDB
+
+The StateDB is intended to be used with the Jellyfish Merkle Tree provided by the sovereign Module System. If you aren't using the
+module system, chances are that you'll want to implement your own State Database.
+
+StateDB is designed to store Jellyfish Merkle Tree data efficiently. It maintains a flat store mapping `(Key, Version)` tuples
+to values, as well as a mapping from JMT `NodeKey`s to JMT `Nodes`.
+
+In the module system, StateDB is abstracted behind the Storage interface, so you won't interact with it directly.